Automatic electric can opener



Sept. 13, 1960 G. coNGDoN AUTOMATIC ELECTRIC CAN OPENER 4 Sheets-Sheet 2 Filed Sept. 21, 1959 INVENTOR. y @wel Conga/ 022 fmum r Sept/13, 1960 G. L. CONGDON AUTOMATIC ELECTRIC CAN OPENER Filed Sept. 2l, 1959 4 Sheets-Sheet I5 INVENTOR.

eoffgl 502561/ 022 SePt- 13, 1960 G. L. coNGDoN 2,952,073

AUTOMATIC ELECTRIC CAN OPENER Filed Sept.4 2l, 1959 A4 Sheets-Sheet 4 l l l l l 1 v INVENTOR. 'G e .C022 dozz Q e055 l j' @fag/Es'.

United States `T'Pateut O AUTOMATIC ELECTRIC CAN OPENER George L. Congdon, Fort Atkinson, Wis., assiguor to Burgess Vibrocrafters, Inc., Grayslake, Ill., a corporation of Delaware Filed Sept. 21, 1959, Ser. No. 841,228

23 Claims. (Cl. 30-4) This invention relates to can openers and more particularly to electric motor driven can openers having certain features for the automatic starting yand stopping of the electric motor.

The principal and general object of the invention is to provide an improved electric motor powered can opener, the improvements residing in the novel operating mechanism which is relatively simple, sturdy and fool proof, whereby the improved can opener may be expected to provide long and trouble-free service.

A further object is to provide such a can opener which may be semi-automatic or completely automatic in operation, as desired, the machine starting and stopping in the latter instance as the result of the mere insertion and withdrawal of the can to be opened and without manual manipulation of any external lever or handle associated with the device.

Other objects `and advantages of the invention will become apparent as the following description of the invention proceeds with reference to the accompanying drawings in which:

Fig. 1 is a front view of the improved electric can opener with a can indicated by dot-dash lines in the position of being opened;

Figs. 2 and 3 `are right side and top views, respectively, of the can opener shown in Fig. 1;

Fig. 4 is a cross-sectional view taken lat the line 4--4 of Figs. 2 and 3 and showing the mechanism in can cutting position;

Fig. 5 is a cross-sectional View taken at the line 5-5 of Fig. 3 and showing the mechanism in can cutting position;

Fig. 6 is a cross-sectional view corresponding to that of Fig. 4 but showing the mechanism in retracted position;

Fig. 7 is a cross-sectional view similar to that of Fig. 6 but showing the mechanism at an intermediate position at which the motor controlling switch is open but the can is retained in position upon the opener;

Figs. 8-12 are detail perspective views of certain vparts of the can opener mechanism, Fig. l1 being an exploded View of the supporting frame, `and Figs. 13 and 14 are side and top views, respectively, of a preferred form of the cutter blade.

As will be understood from this specification of the invention, the electric can opener, when its fullest potentialities are utilized, is capable of being started by the insertion of a can to be opened into the cutting zone without the separate manipulation of any control lever and the operating motor is automatically stopped upon completion of the severing of the lid of the can although the can is still held by the opener until it is grasped and manually removed. As `a safety feature, as well as an aspect of the `automatic operation, the motor driving the can opener can be started only when a can is inserted into the cutting zone in the ordinary use of the device. An operating handle is included with the can opener herein described and illustrated by way of example of the invention, but this is optional when advantage is otherwise taken of the fully automatic features of the unit.

The entire operating mechanism assembly is supported V2,952,073 Patented Sept. 13, 1960 upon a frame shown separately in the exploded view of Fig. l1 and including support plate 1 which, in turn, is supported within `a housing 2 by means of screws 3 threaded into bosses 4 which may constitute an integr-al part of the housing. A re-entrant portion of the housing forms `a pocket 5 for convenient lifting and carrying of the can opener. A front cover `6, having a window '7 therein for exposure of an access to the lid cutting assembly, covers and completes the housing.

A suitable electric motor, designated generally by the numeral 8 and not otherwise described in detail, is mounted upon support plate .1 by means of a suitable bracket 9. The motor shaft 10 carries a wheel 11 for the transmission of its rotary motion to the can opener mechanism, in this particular example, by belt and chain drives.

A relatively heavy bracket 12, shown separately in Fig. 9, carries the moving parts of the can opener mechanism. A stud shaft 13 extends through bracket 12 near the lower extremity thereof and is securely affixed therein. Stud 13 is journalled at 14 in support plate 1 to form a pivot mounting for the bracket upon the support plate. Pulley 1S is mounted upon stud 13 for rotation about this shaft and =a sprocket wheel 16 is fast to the hub 17 of the pulley 15 to be driven thereby and, in turn, to drive wheel 1S by means of chain 19. Pulley 15 is driven by belt 2t).

Shaft 21, to which wheel 18 is keyed or otherwise fastened, is journalled in a bushing 22 which bushing is mounted in openings 23 (Fig. 9) in bracket 12 `and an auxiliary bracket 24 which latter may be permanently welded to the upper part of bracket 12 as indicated at 25. A collar 26 serves to properly space wheel 18 from the supporting bracket structure so that it may be turned freely by the motor and, in turn, drive shaft 21.

A can turning wheel 27, having suitable teeth on the periphery thereof for gripping the lower edge of the bead yat the top of a can, is aixed to the outer end of shaft 21 for rotation thereby.

It will be understood from the foregoing that since the shaft driving the can turning wheel 27 and theV associated driving mechanism `are mounted in and carried by bracket 12 which, in turn, is pivoted by means of stud 13 in the iixed support plate 1, this entire can tur-ning wheel assembly may be moved within limits by swinging the same labout stud 13 whereby the position of the can turning wheel may be shifted from a retracted position `at one extreme to a can opening position at the other.

A channel-like guideway 28 is permanently afxed in horizontal position along the top of support plate 1 Kand becomes a part of the frame assembly. A bracket 29 is welded to ears 30 upstanding from guideway 28 for the iirm and fixed support of this bracket from plate 1 and to complete the opener mechanism supporting frame. This bracket provides support for the cutter blade, control switch and associated parts of the can opener mechafnism. A system of locating notches is provided in the various parts of the frame to receive mating elements of the supported parts, as will be seen from the description of the cutter and switch control mechanism of the can opener. I

The switch which controls the electric motor of the can opener comprises a base in the form of a relatively heavy strip 31 of insulating material carrying two terminals, 32 and 33, which are respectively connected to wires connected with the motor and line conductor 34. Switch Contact 35 is mounted directly in insulating base 31 while the other contact 36 is carried by the free end of a leaf spring conductor 37 which, in turn, is mounted upon the switch base and connected with terminal 32. One end of the switch base is anchored to the end of a screw 38 which is threaded at 39 into a portion of frame 29 and has a knurled head 40 for adjustment of the level of the anchored end of the switch base to thereby adjust the position of the fixed contact 35 in relation to contact 36.

Cutter blade 41 is advantageously formed integrally with a blade supporting plate 42. The cutter blade is turned to extend at approximately right angles, or at an angle of slightly less than ninety degrees to the support- 'mg plate which latter rests loosely and removably in the frame structure, especially upon bracket 29 and guideway 28. The left end of plate 42 is loosely held in notches 43 in ear 30 (Figs. 1l and 7) and thus restrained against vertical movement. The rear corners of plate 42 are notched, as indicated at 44, to limit the extent to which the cutter blade and supporting plate may be moved into the assembly upon insertion of the cut-ter blade into the can opener structure. It will be noted that the right end of plate 42 is not confined by notches comparable to notches 43, this end of the plate being free to move up and down to operate the switch in a manner hereinafter more fully described. Upward movement of the plate and blade is limited by the top of notch 60 (Fig. 5) in cover plate 59. Certain refinements in the form of the cutter blade are shown in Figs. 13 and 14. While not indispensable to the successful operation of the device, the particular form of the blade shown in these figures has been found to assure the complete cutting of lids of cans of somewhat heavy gauge or unusually heavy side seams and it is therefore here disclosed in detail.

The blade is bent to an angle of approximately 86 to the plane of plate 42, The cutting edge slants at an angle of approximately 21 to the plane of plate 42, or about 69 to the vertical median line of the blade. Outer bevel 41a is at an angle of approximately 45 to the adjoining surface of the cutter blade, while inner bend 41b is at an angle of approximately 66 to the blade. The bevels forming the edge of the blade meet at a juncture line 41e,` which is not parallel to the sides of the blade, but rather slants inwardly from the leading to the following end of the blade edge. This slanting of what may be regarded as the actual cutting edge of the blade may be established by grinding the outer and inner bevels at slightly different angles to plate 42, the angle of inner bevel 41b being slightly larger.

Although the exact reason for the superior operation of the blade shown in Figs. 13 and 14 is not known with certainty, it is believed that the inclination of inner bevel 41b and the slant of the cutting edge 41C both contribute to a tendency to guide the leading edge of the blade somewhat away from the rim of the can being cut and, at the same time, pressing the rim tightly to the turning wheel, with the result that continued turning of the can until completion of the cutting operation is assured.

A leaf spring 45 is also supported within the supporting frame, being located and held in position by notches 46 and cooperating ears 47 extending laterally from the sides of spring 45. The head of the spring is retroverted to form a socket for lthe reception of plate 42 of the cutter blade, while tail end 49 is inclined for purposes hereinafter explained. The cutter plate 42 overlies spring 45 and the retroverted portion 48 tends to urge the free right end of plate 42 downwardly upon the application of an upward force to the tail end 49 of the spring. Since the left end of plate 42 is restrained against upward movement by notches 43, leaf spring 45 can bear or fulcrum against the under side of the plate at this location.

With this arrangement, it will be understood that the switch is normally open. Without regard to the effect of leaf spring 45, spring arm 37 of the switch structure presses continuously downwardly to hold plate 42 and cutter blade 41 down at its lowermost position, keeping the switch open. An upward force applied to the blade would close the switch by moving the right side of plate 42 upwardly against the pressure of spring 37. An insulating strip or block 36a is interposed between the free end of spring conductor 37 and the underlying structure.

An arcuate slot 50 (Fig. l1) is provided in guideway 28 and plate 1, the center of curvature being at opening 13a in which stud 13 is journalled. Bushing 22 and shaft 21 pass through this slot, permitting the limited swinging movement of bracket 12 and the can turning wheel assembly about stud 13. A friction plate 51 having a vertically elongated opening 52 therein and bentin end portions 53 is arranged to slide horizontally in guideway 23, the slot 52 accommodating bushing 22 and shaft 21 of the can turning wheel. The functions of plate 51 are to provide some impedance to the swinging movements of bracket 12 and to cover slot 50.

Auxiliary bracket 24 includes a foot 54 which extends up into a socket 55 in an elongated operating button 56 which is retained between the edges of housing 2 and front cover 6 at the top of the can opener for sliding from one side to the other as bracket 12 swings between its extreme positions. A tail piece 57 having an inclined upper edge 58 is advantageously formed as a part of auxiliary bracket 24. In the can opener assembly, tail piece 57 engages the tail end 49 of leaf spring 45 at certain positions of the operating mechanism. Upward pressure applied to the tail end of the leaf spring by the tail element 57 tends to augment the spring force of spring arm 37 of the switch to urge the cutter blade downwardly. The inclined edge 58 of tail piece 57 serves as a cam surface for increasing the tension in leaf spring 45 as the bracket assembly approaches its extreme clockwise (can opening) position, so that the spring forces tending to open the switch are at their greatest magnitude when the can turning wheel and supporting bracket assembly are at the can opening position.

The can opener structure thus described is completed by a cover plate 59 which holds the cutter blade plate 42 in its proper position and covers the otherwise exposed switch mechanism. A notch 60 is provided in plate 59 to accommodate the cutter blade 41. The top of this notch also serves as 4a stop to limit the upward movement of the cutter blade and thus of the switch activating cutter blade plate 42. Since cover plate 59 must be removed to replace the cutter blade or adjust the switch, it is conveniently fastened to the supporting frame of the can opener by means of knurl-headed screws 61 threaded into holes 62. If desired, a bracket 63 may be provided as a part of cover plate 59 to support a permanent magnet 64 for holding the lid of a can after it is severed in the can opening operation.

The can opener herein shown and described by way of example of the invention contemplates rotation of the can driving wheel 27 in a counterclockwise direction. The slanting edge of cutter blade 41 is, accordingly, inclined from left to right so that the turning of a can being opened by the can turning wheel forces the metal being cut against the inclined edge. The mechanism is arranged to permit the swinging movement of bracket 12 carrying the can turning wheel assembly between a retracted position at which the turning wheel is below and to the left of the cutter blade, as shown in Fig. 6, and a can opening position at which the can turning wheel is in vertical alignment with, and in back of, the cutter blade as shown in Fig. 4. These two positions represent the extremes of permissible swinging movement of bracket 12 and the can turning wheel assembly. At an intermediate position, shown in Fig. 7, the can turning wheel is shifted a short distance to the left and, since the bracket carrying the Wheel is pivoted at the shaft 13, somewhat lower than the position of the can turning wheel in can cutting position. Pivot 13 is located slightly to the right of a vertical line depending from the cutter blade.

The normal position of the can opener mechanism when not in use is the retracted position as illustrated in Fig. 6. At this position, the switch is open and the motor inactive. To open a can, the can is placed in position with the top bead or rim in place upon the teeth of the can turning wheel, the rim of the can being brought under and in back of the edge of the cutter blade. Then, to start the motor and initiate the cutting operation, control button 56 may be manually shifted to the right, forcing the can upwardly as bracket 12 is thus rotated in a clockwise direction, the upward movement of the can forcing the cutter blade and, with it, plate 42 upwardly to close the switch. Alternatively, the can, after insertion into initial position, is tilted somewhat to serve as a lever bearing down upon the can turning wheel and up against the cutter blade to close the switch and start the motor in operation. In either case, the initial rotation of the can turning wheel, gripping the rim or bead of the can, brings about movement of the bracket 12 to the nal can cutting position of the can turning wheel immediately under and in back of the cutter blade for completion of the severing of the lidof the can.

The initial piercing of the lid is thus brought about by the turning of the wheel by the motor. The switch is maintained in closed position after the piercing of the lid and during the entire cutting process due to the inclination of the cutting edge whereby the resistance of the metal to cutting continuously presses the cutter blade upwardly to keep the switch closed. When the lid has been completely severed, this upward force is discontinued and the cutter blade, together with the right side of cutter blade plate 42, shifts downwardly responsive to the combined forces of springs 37 and 45. This movement opens the switch and stops the motor. The Vcan is still held between the wheel and the blade in the can opener with the motor inoperative. The opened can may then be removed by grasping it and moving it slightly to the left to shift the can turning wheel away from the blade toward t-he retracted position and permitting the ready withdrawal of the opened can from the apparatus. This operation is assisted somewhat by the pressure of the tail portion 49 of spring 45 against the inclined edge 58 of the tail 57 of auxiliary bracket 24. The severed lid of the can is retained by magnet 64. The operating button 56 may, of course, be used if desired, in facilitating removal of the opened can from the can opener.

It will be noted that the form and dimensions of the tail portion 49 of spring 45 and the cooperating tail 57 of auxiliary bracket 24 are such that movement of the can turning wheel assembly between the retracted and intermediate positions does not bring the spring 45 into play, while distortion of the spring member is progressively increased as the can turning wheel assembly is moved from the intermediate position to the can opening position. Thus, a comparatively small force exerted upwardly by the lid of the can against the cutter blade is suicient to close the switch. Conversely, the spring force exerted by spring 45 tending to open the switch upon completion of the lid cutting operation is greatest in the can opening position whereby upon completion of the cut the desired opening of the switch and stoppage of the motor is assured. This spring pressure gradually diminishes as the intermediate position is approached. The friction strip 51 provides suflicient drag to hold the c an turning wheel assembly at the desired positions, especially the can cutting position following cutting of the lid, to prevent accidental dropping of the opened can.

. The position of fixed switch contact 3S may readily be adjusted by turning screw 38 to insure proper automatic operation of the can opener. This screw is readily accessible upon removal of cover plate 59. Removal of this cover plate also permits replacement of the cutter blade as required.

The particular form of electric can opener herein shown and described is merely one example of the invention. The arrangement and specific forms of the several parts may be altered, but such devices which employ the inventive concept herein disclosed are intended to be included within the scopeof the appended claims as the equivalent of the example specifically described.

Invention is claimed as follows: p

l. A can opener comprising a supporting frame, an electric motor and a switch therefor mounted upon said frame, a cutter blade having an inclined edge supported near the top of said frame with a degree of freedom for vertical movement, a bracket pivotally mounted in said frame below said blade, a can turning wheel journalled in said bracket, transmission means operatively interconnected between said motor and said can turning wheel for turning said wheel, and means responsive to the position of said cutter blade for closing said switch when said blade is elevated and opening said switch when said blade is lowered, the arrangement of said bracket being such that movement thereof moves said can turning wheel between can cutting position below and behind said blade and retracted position away from said blade whereat a can can be inserted and removed from cutting position on said can opener.

2. A can opener in accordance with claim l and including spring means pressing the cutter blade downwardly.

3. A can opener in accordance with claim 2 wherein the magnitude of the spring pressure pressing downwardly upon the cutter blade is such that it may be overcome -to close the switch by pressure exerted upwardly at the edge of said blade by the lid of a can and the degree of inclination of said edge of said blade is such that the resistance to cutting of the metal of the lid of a can being opened exerts a vertical component of force to said blade suicient to overcome said spring pressure and maintain said switch closed while the lide is being cut in the normal operation of said can opener.

4. A can opener in accordance with claim 2 wherein the magnitude of the spring pressure is suicient -to move the cutter blade downwardly and open the switch when the lid of a can being opened has been completely cut from the can.

5. A can iopener in accordance with claim 7 wherein the spring means includes a leaf spring whereof one end is connected with the cutter .blade Iand the other end is free, said bracket including a tail piece rigidly extending therefrom and having an inclined cam surface arranged to engage said free end of said leaf spring, the arrangement being such that movement of said bracket toward can cutting position loads said leaf spring -to increase the downward pressure -applied Ithereby to the cutter blade.

6. A can opener in accordance with claim 2 wherein the spring means includes a leaf spring whereof one end is connected with the cutter blade and the other end is free, said bracket including 'a tail piece rigidly extending therefrom and having an inclined cam surface arranged to engage said `free end of said leaf spring, the arrangement being such that movement of said 4bracket toward can cutting position loads said leaf spring to pr-ogressively increase the magnitude of the pressure applied to the cutter `blade to a maximum value at the can cutting positlon.

7. A can opener in accordance with claim 2 wherein the spring means includes a leaf spring whereof one end is connected with the cutter blade and the other end is free, said -bracket including a tail piece rigidly extending therefrom and having an inclined cam surface arranged to engage said free end of said leaf spring, the arrangement being such that said `tail piece engages said free end of said leaf spring only at positions of said bracket between an intermediate position and the can cutting position thereof and movement of said bracket toward can cutting position from said intermediate position loads said leaf spring to increase the downward pressure applied thereby to the cutter blade.

8. A can opener in accordance with claim 1 and including a housing wherein the supporting -frame is mounted and an operating member fast to said bracket and extending through said housing for manually moving said bracket between can cutting and retracted positions.

9. A can opener in accordance with claim 1 wherein the characteristics of the motor and transmission means are such that in normal operation of said can opener the can turning wheel is rotated to cause the upper peripheral portion of said wheel -to move in a predetermined sidewise direction, the retracted position of said wheel is in said predetermined direction from the cutter blade, the edge of said blade is inclined in a direction opposite to said predetermined direction, and the bracket is pivoted at a location slightly spaced in the direction opposite to said predeter-mined direction from a vertical line depending from said cutter blade.

10. A can opener in accordance with claim 1 and including friction means for impeding movement of the can turning wheel between retracted and can cutting positions whereby said wheel maintains a given position until moved with positive force.

ll. A can opener in accordance with claim l wherein the Atransmission means comprises two stages and includes an intermediate shaft, a driven Wheel of the first stage and a driving wheel of the second stage carried upon said shaft and fixed against rotation relative to each other, said shaft forming the pivot `of the bracket whereby said transmission is operative to turn lthe can turning wheel at any position thereof between retracted and can cutting positions.

l2. A can opener in accordance with claim l wherein the transmission means comprises two stages and includes an intermediate shaft, a driven wheel of the first stage and a driving wheel of the second stage carried upon said shaft `and fixed against rotation relative to each other, said shaft being fixedly mounted in the bracket and journalled in the supporting frame to form the pivot of said bracket whereby said transmission is operative to turn the can turning wheel at any position thereof between retracted and can cutting positions.

13. A can opener in accordance with claim 1 wherein the cutter blade extends downwardly and inwardly toward the supporting frame at an angle of approximately 86 to horizontal and the edge thereof is inclined at an angle of approximately 21 yto horizontal, said edge being formed by outer and inner bevels of approximately 45 and 66, respectively.

14. In an electric can opener having supporting structure, a cutter blade having a downwardly directed inclined edge, said blade being vertically resiliently supported in said structure, a normally open switch supported in said structure Iabove said blade, means operatively connecting said blade with said switch to cause closure of said switch when said Iblade is moved upwardly and opening of said switch when said blade is moved downwardly, and means for bringing lthe lid of a can to be opened to bear upwardly against said edge of said blade to move said lblade upwardly to close said switch, said last-mentioned means comprising a can turning wheel movably supported in said structure and adapted to engage the under surface of the bead at the top of -a can.

15. The device `of claim 14 wherein the can turning Wheel is so mounted in the structure that movement thereof is confined to positions on a generally inclined path Ibetween a retracted position at one side of and lower than the cutter blade and a can cutting position behind and below said blade but higher than the retracted position.

16. The device of claim 14 and including means for adjusting the position of the switch.

17. The device of claim 14 wherein the can turning wheel is 4so mounted in the structure that movement thereof is confined to positions on a generally inclined path between a retracted position at one side of and lower than the cutter blade and a can cutting position behind and below said blade but higher than the retracted position, and including a spring biasing the switch toward open position, and spring means pressing the cutter blade downwardly and means for progressively increasing lthe magnitude of the pressure exerted by said spring means as the can turning wheel approaches can cutting position.

18. A can opener comprising a housing, a supporting frame including a vertical support plate mounted in said housing, an electric motor mounted upon said plate, a normally open switch electrically connected with said motor and mounted in the upper part of said frame, a channel-like guideway horizontally mounted upon the upper portion of said vertical support plate, a vertically movable cutter blade support plate horizontally arranged under said switch to control the same, a cutter blade attached to said blade support plate and extending downwardly outside of said guideway and said housing, a leaf spring adapted to press said blade support plate down wardly, a bracket pivotally mounted on said vertical support plate below said cutter blade and slightly to the right of a vertical line depending therefrom, a can turning wheel shaft journalled in the upper part of said bracket and a can turning wheel fast thereto and exposed outside of said guideway and said housing for cooperation with said cutter blade, a brake strip arranged for frictional movement in said guideway and having an opening therein through which said can turning wheel passes, an intermediate shaft iixedly mounted in said bracket and journalled in said vertical support plate to form the pivot for said bracket, a driven wheel upon said intermediate shaft connected for rotation by said motor, a sprocket upon said intermediate shaft in fixed relation to said driven wheel, a toothed wheel fixed upon said can turning wheel shaft, and a chain entrained around said sprocket and said toothed wheel, said bracket being free to swing about said intermediate shaft between retracted and can cutting positions, the arrangement being such that movement of said bracket and can turning wheel carried thereby with a can in position thereon to be opened toward said can cutting position causes the lid of the can to force said blade and said blade supporting plate upwardly to close said switch and cause the motor to start and turn the can turning wheel whereupon to first pierce the lid of the can and then cut the lid thereupon whereafter the spring pressing downwardly upon said cutter blade support plate causes said plate to move downwardly and permit said switch to open and stop said motor.

19. A can opener in accordance with claim 18 and including a foot extending from the bracket to the exterior of the housing for manual manipulation of said bracket.

20. A can opener in accordance with claim 18 and including means for adjusting the position of the switch with respect to the cutter blade support plate.

2.1. For use with a can opener, a vertical cutter blade having an inclined edge formed by outer and inner bevels meeting at a juncture line, said edge being disposed at an angle of approximately 69 to the vertical blade, the angles of said outer and inner bevels with the adjoining surfaces of the blade being approximately 45 and approximately 66, respectively.

22. A cutter blade in accordance with claim 2l wherein the juncture line of the outer and inner bevels extends from the leading to the following end of the edge of said blade in a direction starting inwardly toward the side of said blade which engages` the rim of a can during the cutting operation.

23. lFor use with a can opener, a cutter blade and supporting assembly comprising a cutter blade in accordance with claim 21 and a supporting plate integral with said blade and defining an angle of approximately 86 with the side of said blade adjoining the inner bevel of the edge thereof.

Girard Nov. 24, 1931 Jeppsson Feb. 5, 1935 

